CBSE Class 12 Chemistry Biomolecules MCQs Set 04

Question: The a-amino acid which does not give purple colour in the ninhydrin test is 
(a) proline
(b) glycine
(c) lysine
(d) aspartic acid
Answer: a  

Question: Which of the following describes the overall three dimensional folding of a polypeptide? 
(a) Primary structure
(b) Secondary structure
(c) Tertiary structure
(d) Quaternary structure
Answer: c

Question: If one strand of DNA has the sequence TATGACTG, the sequence in the complimentary strand would be 
(a) ATACAC T C
(b) ACGTTGAC
(c) ATACTGAC
(d) ATACTGCA
Answer: c

Question: Which of the following compound shows aromatic properties?
(a) Valine
(c) Serine
(b) Leucine
(d) Tyrosine
Answer: d  

Question: Monomer of nucleic acid is
(a) nucleotides
(b) nucleoxides
(c) aminoacids
(d) carboxylic acid
Answer: a

Question: The main structural feature of protein is 
(a) ester linkage
(b) ether linkage
(c) peptide linkage
(d) All of these
Answer: c

Question: Hydrolysis of proteins give
(a) α-amino acids
(b) β-amino acids
(c) ϒ-amino acids
(d) mixture ofall, i.e.α,βϒ-amino acids
Answer: a

Question: Zwitter ion is formed by
(a) aniline
(b) acetanilide
(c) benzoic acid
(d) glycine
Answer: d

Question: Pick out the one which does not belong to the family.
(a) Pepsin
(b) Cellulose
(c) Ptyalin
(d) Lipase
Answer: b

Question: In alkaline medium, alanine exits predominantly as
(a) anion
(b) Zwitter ion
(c) cation
(d) covalent form 
Answer: a

Question: 1.78 g of an optically active L-amino acid (A) is treated with Na NO₂ /HCI at 0°C, 448 cm³ of nitrogen was at STP is evolved. A sample of protein has 0.25% of this amino acid by mass. The molar mass of the protein is
(a) 36500 g mol - 1
(b) 34500 g mol - 1
(c) 35400 g mol - 1
(d) 35600 g mol - 1
Answer: d

Question: Polypeptides having molecular weights above 10000 are known as 
(a) amino acids
(b) hormones
(c) proteins
(d) terminal amino acids
Answer: c

Question: The compound, which give a positive ninhydrin test and a negative Benedict's solution test, is 
(a) a monosaccharide
(b) a disaccharide
(c) a lipid
(d) a protein
Answer: d

Question: Biuret test is not given by
(a) carbohydrates
(c) urea
(b) polypeptides
(d) proteins
Answer: a

Question: Which of the following is a heterocyclic amino acid?
(a) Glycine
(b) Alanine
(c) Phenylalanine
(d) Tryptophan
Answer: d

Question: Denaturation of proteins leads to the loss of its biological activity by 
(a) formation of amino acids
(b) loss of primary structure
(c) loss of both primary and secondary structures
(d) loss of both secondary and tertiary stuctures
Answer: d

Question: Which one of the following does not correctly match with each other?
(a) Silk-polyamide
(b) Lipase-enzyme
(c) Butter-fat
(d) Oxytocin-enzyme
Answer: d

Question: Which of the following hormone, is responsible for the growth of animals? 
(a) Auxin
(b) Insulin
(c) Adrenaline
(d) Somatotropin
Answer: d

Question: An example of a sulphur containing amino acid is 
(a) lysine
(b) serine
(c) cysteine
(d) tyrosine
Answer: c  

Question: Which amino acid has phenyl—OH group? 
(a) Lysine
(b) Arginine
(c) Proline
(d) Tyrosine
Answer: d  

Question: Which of the following is an amphoteric acid?
(a) Glycine
(b) Salicylic acid
(c) Benzoic acid
(d) Citric acid
Answer: a

Question: Amino acids have peptide linkage which is 
(a) —CO—NH—
(b) —C—NH₂
(c) SO—NH—
(d) —CO—N—
Answer: a

Question: A tetrapeptide has - COOH group on alanine. This produces glycine (Gly), valine (Val), phenyl alanine (Phe) and alanine (Ala), on complete hydrolysis. For this tetrapeptide, the number of possible sequences (primary structures) with — NH₂ group attached to a chiral centre is
(a) 7
(b) 5
(c) 4
(d) 8
Answer: c  

Question: Which of the following will explain synthesis of RNA?
(a) Translation
(b) Coagulation 
(c) Transcription
(d) Replication
Answer: c

Question: The number of disulphide linkages present in insulin are
(a) 1
(b) 2
(c) 3
(d) 4
Answer: b

Question: Dialysis can be used to separate 
(a) protein and starch
(b) glucose and protein
(c) glucose and NaCl
(d) glucose and fructose
Answer: b

Question: The amino acid which is not optically active is
(a) lactic acid
(b) serine
(c) alanine
(d) glycine
Answer: d

Question: The number of amino acids and number of peptide bonds in a linear tetrapeptide (made of different amino acids, are respectively 
(a) 4 and 4
(b) 5 and 5
(c) 5 and 4
(d) 4 and 3 
Answer: d

Question: A compound with molecular mass 180 is acylated with CH₃COCI to get a compound with molecular mass 390. The number of amino groups present per molecule of the former compound is 
(a) 2
(b) 5
(c) 4
(d) 6
Answer: c

Question: Which of the following set consists only of essential amino acids?
(a) Alanine, tyrosine, cystine
(b) Leucine, lysine, tryptophane
(c) Alanine, glutamine, lycine
(d) Leucine, proline, glycine 
Answer: b

Question: The presence or absence of hydroxy group on which carbon atom of sugar differentiates RNA and DNA ?
(a) 1st
(b) 2nd 
(c) 3rd
(d) 4th
Answer: b

Question: Which one of the following statements is correct? 
(a) All amino acids except lysine are optically active
(b) All amino acids are optically active
(c) All amino acids except glycine are optically active
(d) All amino acids except glutamic acids are optically active.
Answer: c  

Question: Which one is not a constituent of nucleic acid? 
(a) Uracil
(b) Guanidine
(c) Phosphoric acid
(d) Ribose sugar 
Answer: b

Question: The reason for double helical structure of DNA is operation of 
(a) van der Waals' forces
(b) dipole-dipole interaction
(c) hydrogen bonding
(d) electrostatic attractions
Answer: c  

Question: At pH = 4, glycine exists as
(a) H₃N⁺—CH₂ — COO^-
(b) H₃N⁺—CH₂ — COOH
(c) H₂N—CH₂ — COOH
(d) H₂N—CH₂ — COO^-
Answer: b  

Question: A decapeptide (mol. wt. 796) on complete hydrolysis gives glycine (mol. wt. 75), alanine and phenylalanine. Glycine contributes 47% to the total weight of the hydrolysed products. The number of glycine units present in the decapeptide is
(a) 3
(b) 4
(c) 5
(d) 6
Answer: d  

Question: A Zwitter ion is 
(a) negatively charged ion without metal atom
(b) a heavy ion with a small charge on it
(c) an ion with positive and negative charge at different points on it
(d) a positively charged ion without a metal atom
Answer: c

Question: In an alkaline medium, glycine predominantly exists as/in a/an 
(a) cation
(b) anion
(c) Zwitter ion
(d) covalent form 
Answer: b

Question: The correct statement in respect of protein haemoglobin is that it 
(a) functions as a catalyst for biological reactions
(b) maintains blood sugar level
(c) act as an oxygen carrier in the blood
(d) forms antibodies and offers resistance to diseases 
Answer: c